U.S. patent application number 13/664732 was filed with the patent office on 2014-05-01 for systems and methods for analyzing flowback compositions in real time.
The applicant listed for this patent is HALLIBURTON ENERGY SERVICES, INC.. Invention is credited to Patrick Matthew Ljungdahl, Sean A. Roach, Alexis Wachtel, II.
Application Number | 20140121970 13/664732 |
Document ID | / |
Family ID | 50548095 |
Filed Date | 2014-05-01 |
United States Patent
Application |
20140121970 |
Kind Code |
A1 |
Ljungdahl; Patrick Matthew ;
et al. |
May 1, 2014 |
Systems and Methods for Analyzing Flowback Compositions in Real
Time
Abstract
A sensor assembly includes an optical computing device having an
integrated computational element (ICE) configured to optically
interact with a fluid stream and detect a first characteristic of a
substance within the fluid stream. The optical computing device is
configured to generate a first signal corresponding to the first
characteristic. The sensor assembly also includes a parameter
sensor configured to measure a second characteristic of the fluid
stream and generate a second signal corresponding to the second
characteristic and a processor communicatively coupled to the
optical computing device and the parameter sensor. The processor is
configured to receive the first and second signals and determine a
mass flow rate of the substance.
Inventors: |
Ljungdahl; Patrick Matthew;
(Houston, TX) ; Roach; Sean A.; (Houston, TX)
; Wachtel, II; Alexis; (Houston, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HALLIBURTON ENERGY SERVICES, INC. |
Houston |
TX |
US |
|
|
Family ID: |
50548095 |
Appl. No.: |
13/664732 |
Filed: |
October 31, 2012 |
Current U.S.
Class: |
702/6 |
Current CPC
Class: |
E21B 49/08 20130101;
G01F 1/86 20130101; G01F 1/7086 20130101; E21B 47/00 20130101; E21B
21/067 20130101; G01F 1/74 20130101; G01N 21/31 20130101; E21B
49/005 20130101; G01F 1/661 20130101 |
Class at
Publication: |
702/6 |
International
Class: |
E21B 47/00 20060101
E21B047/00; G01F 1/66 20060101 G01F001/66; G01F 1/86 20060101
G01F001/86 |
Claims
1. A system, comprising: a separator configured to accept and
separate a multiphase flowback effluent stream into a plurality of
secondary streams; a first sensor assembly arranged to monitor the
flowback effluent stream and generate a first signal corresponding
to at least one characteristic of the flowback effluent stream, the
first sensor assembly including a first optical computing device
having an integrated computational element (ICE) configured to
optically interact with the flowback effluent stream; a second
sensor assembly arranged to monitor one of the plurality of
secondary streams and generate a second signal corresponding to at
least one characteristic of the one of the plurality of secondary
streams, the second sensor assembly including a second optical
computing device having an ICE configured to optically interact
with the one of the plurality of secondary streams; and a signal
processor configured to receive the first and second signals and
determine a mass flow rate of a substance present in both the
flowback effluent stream and the one of the plurality of secondary
streams.
2. The system of claim 1, wherein the plurality of secondary
streams comprise one or more of a solids secondary stream, an oil
secondary stream, a water secondary stream, and a gas secondary
stream.
3. The system of claim 1, wherein the at least one characteristic
of the multiphase flowback effluent stream comprises a
concentration of the substance of the multiphase flowback effluent
stream.
4. The system of claim 1, wherein the at least one characteristic
of the multiphase flowback effluent stream comprises a velocity of
the multiphase flowback effluent stream.
5. The system of claim 1, wherein each ICE generates optically
interacted light and the first and second optical computing devices
each further include a detector arranged to receive the optically
interacted light from its respective ICE and generate at least a
portion of the first and second signals, respectively.
6. The system of claim 5, wherein the second optical computing
device comprises a plurality of ICEs and the detector in the second
optical computing device is arranged to receive optically
interacted light from the plurality of ICEs and generate a
corresponding plurality of individual output signals, wherein the
second signal comprises at least a portion of the plurality of
individual output signals.
7. The system of claim 1, where one or both of the first and second
sensor assemblies includes a multiphase fluid parameter sensor
configured to measure a velocity of the flowback effluent stream
and/or the one of the plurality of secondary streams, respectively,
the multiphase fluid parameter sensor comprising a plurality of ICE
and at least one detector configured to generate at least a portion
of the respective first and second signals.
8. The system of claim 7, wherein one or both of the first and
second sensor assemblies further includes a densometer configured
to measure a density of the respective flowback effluent stream
and/or the one of the plurality of secondary streams, respectively,
and convey a third signal corresponding to the density to the
signal processor.
9. A sensor assembly, comprising: an optical computing device
having an integrated computational element (ICE) configured to
optically interact with a fluid stream and detect a first
characteristic of a substance within the fluid stream, the optical
computing device being configured to generate a first signal
corresponding to the first characteristic; a parameter sensor
configured to measure a second characteristic of the fluid stream
and generate a second signal corresponding to the second
characteristic; and a processor communicatively coupled to the
optical computing device and the parameter sensor, the processor
being configured to receive the first and second signals and
determine a mass flow rate of the substance.
10. The sensor assembly of claim 9, wherein optically interacted
light is generated through optical interaction of the ICE with the
fluid stream and the optical computing device further includes a
detector arranged to receive the optically interacted light and
generate the first signal.
11. The sensor assembly of claim 10, wherein the optical computing
device is a first optical computing device and the parameter sensor
comprises a second optical computing device including a plurality
of ICEs configured to optically interact with the fluid stream and
generate optically interacted light and at least one detector
arranged to receive the optically interacted light from at least
one of the plurality of ICEs and respectively generate at least one
of a plurality of individual output signals, the parameter sensor
being further configured to generate the second signal based at
least in part on a portion of the plurality of individual output
signals.
12. The sensor assembly of claim 10, wherein: the optical computing
device is a first optical computing device; the parameter sensor
comprises a second optical computing device including an ICE
configured to optically interact with the fluid stream and generate
optically interacted light and a detector arranged to receive the
optically interacted light and generate the second signal; the ICE
of the first optical computing device being configured to interact
with the fluid stream at a first point along a flow path and the
ICE of the second optical computing device being configured to
interact with the fluid stream at a second point along the flow
path that is spaced apart from the first point; and the processor
being further configured to determine a velocity of the fluid
stream based at least in part on the first and second signals.
13. The sensor assembly of claim 12, wherein the flow path is
fluidly coupled to an inlet of a separator and the fluid stream is
a flowback effluent stream being conveyed to the separator for
processing.
14. The sensor assembly of claim 12, wherein the flow path is
fluidly coupled to an outlet of a separator and the fluid stream is
a secondary stream resulting from a separation process undertaken
within the separator of a flowback effluent stream.
15. The sensor assembly of claim 14, wherein the processor is
configured to determine at least one of a quality and a mass flow
rate of the substance in the secondary stream.
16. The sensor assembly of claim 9, wherein the parameter sensor
further comprises a densometer configured to measure a density of
the fluid stream and convey a third signal corresponding to the
density of the fluid stream to the signal processor.
17. A method, comprising: determining a concentration of a
substance in a flow of a fluid with an optical computing device
including at least one integrated computational element (ICE)
configured to optically interact with the fluid; determining a mass
flow rate of the flow of the fluid; and determining a mass flow
rate of the substance.
18. The method of claim 17, wherein the at least one ICE comprises
a first ICE and a second ICE, and determining a mass flow rate of a
flow comprises: detecting with the first ICE a characteristic of
the fluid at a first point along a flow path containing the fluid;
detecting the characteristic of the fluid with the second ICE at a
second point along the flow path, the second point being separated
a distance downstream of the first point; measuring an elapsed time
between detection of the characteristic of the fluid with the first
and second ICE; and determining a velocity of the flow of the fluid
by dividing the distance by the elapsed time.
19. The method of claim 18, wherein determining a mass flow rate of
the flow of the fluid further comprises: measuring a density of the
fluid in the flow of fluid; and multiplying the density by the
velocity.
20. The method of claim 19, wherein measuring the density of the
fluid in the flow of fluid is accomplished using a densometer.
21. The method of claim 17, wherein the fluid is a secondary stream
resulting from a separation process undertaken within a separator
of a flowback effluent stream.
Description
BACKGROUND
[0001] The present invention relates to the separation of a
flowback effluent stream and, in particular, to systems and methods
for the real-time analysis of the composition of an input flowback
effluent stream or one or more separated output effluent
streams.
[0002] Flowback is the discharge of an effluent stream of mixed
materials that is generated during a remedial operation directed,
for example, toward well completion or fracture stimulation. The
flowback effluent stream may contain one or more of water, liquid
hydrocarbons, chemical additives, cuttings, abrasives, proppants,
suspended solids, emulsions, and entrained gases. Disposal of this
effluent stream may be difficult and costly, depending on the
particular composition of the effluent stream, in light of
environmental regulations and responsible corporate behavior. With
the increased use of hydraulic fracturing to increase the
productivity of certain reservoirs, future environmental regulatory
requirements may require an accounting of the amount of chemicals
introduced into a wellbore as well as the amount removed in an
effluent stream in a hydraulic fracturing operation.
[0003] Most hydrocarbon-bearing reservoirs produce a mixture of oil
and/or gas together with water, usually in the form of brine, and
large amounts of dissolved minerals or precipitates, mostly common
salts. In fact, in some oil wells, water and other by-products can
amount to as much as eighty to ninety percent of the total
production yield. This is particularly true during the later stages
of production. Somewhere in the production process the produced
mixture undergoes a separation process where the oil/gas is
separated from the remaining components of the mixture and
subsequently delivered to a refinery for treatment. The water and
remaining components are usually removed from the hydrocarbons
using one or more single phase or multi-phase separation devices.
Generally, these devices operate to agglomerate and coalesce the
produced hydrocarbons, thereby separating them from the water and
other components of the produced mixture. Similar separation
processes may be used to process a flowback effluent stream.
[0004] In some production and flowback cases, the separated water
and other components are able to be pumped back into the ground,
perhaps in some borehole neighboring the one from which it was
removed. This process simply replaces a portion of the liquid
removed from the reservoir, but also simultaneously serves to
maintain required formation pressures for efficient production
rates. In offshore applications, it is often desirable to discharge
the produced water directly into the surrounding ocean, thereby
eliminating the expense of pumping the fluid back downhole.
[0005] Before the water can be discharged into the ocean, however,
or any other body of water (e.g., rivers, lakes, streams, etc. in
other applications) it must first be rigorously tested to make sure
that it does not contain any oil or other impurities that could
damage the surrounding sea life. As environmental regulations
increasingly become more stringent with respect to the disposal of
produced water into the ocean, it becomes increasingly crucial to
obtain accurate and timely analysis of the separated fluids to
ensure compliance with the regulations.
SUMMARY OF THE INVENTION
[0006] The present invention relates to the separation of a
flowback effluent stream and, in particular, to systems and methods
for the real-time analysis of the composition of an input flowback
effluent stream or one or more separated output effluent
streams.
[0007] In some embodiments, a system is disclosed and may include a
separator configured to accept and separate a multiphase flowback
effluent stream into a plurality of secondary streams, a first
sensor assembly arranged to monitor the flowback effluent stream
and generate a first signal corresponding to at least one
characteristic of the flowback effluent stream, the first sensor
assembly including a first optical computing device having an
integrated computational element (ICE) configured to optically
interact with the flowback effluent stream, a second sensor
assembly arranged to monitor one of the plurality of secondary
streams and generate a second signal corresponding to at least one
characteristic of the one of the plurality of secondary streams,
the second sensor assembly including a second optical computing
device having an ICE configured to optically interact with the one
of the plurality of secondary streams, and a signal processor
configured to receive the first and second signals and determine a
mass flow rate of a substance present in both the flowback effluent
stream and the one of the plurality of secondary streams.
[0008] In other embodiments, a sensor assembly is disclosed. The
sensor assembly may include an optical computing device having an
integrated computational element (ICE) configured to optically
interact with a fluid stream and detect a first characteristic of a
substance within the fluid stream, the optical computing device
being configured to generate a first signal corresponding to the
first characteristic, a parameter sensor configured to measure a
second characteristic of the fluid stream and generate a second
signal corresponding to the second characteristic, and a processor
communicatively coupled to the optical computing device and the
parameter sensor, the processor being configured to receive the
first and second signals and determine a mass flow rate of the
substance.
[0009] In yet other embodiments, a method is disclosed that may
include determining a concentration of a substance in a flow of a
fluid with an optical computing device including at least one
integrated computational element (ICE) configured to optically
interact with the fluid, determining a mass flow rate of the flow
of the fluid, and determining a mass flow rate of the
substance.
[0010] The features and advantages of the present invention will be
readily apparent to those skilled in the art upon a reading of the
description of the preferred embodiments that follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The following figures are included to illustrate certain
aspects of the present invention, and should not be viewed as
exclusive embodiments. The subject matter disclosed is capable of
considerable modifications, alterations, combinations, and
equivalents in form and function, as will occur to those skilled in
the art and having the benefit of this disclosure.
[0012] FIG. 1 depicts an exemplary system for the real-time
analysis and separation of a flowback effluent, according to one or
more embodiments.
[0013] FIG. 2 is a block diagram of an embodiment of an real-time
flowback effluent analysis, according to one or more
embodiments.
[0014] FIG. 3 illustrates an exemplary integrated computation
element, according to one or more embodiments.
[0015] FIG. 4 illustrates an exemplary measurement system for
monitoring a fluid present in a flow path, according to one or more
embodiments.
[0016] FIG. 5 illustrates another exemplary measurement system for
monitoring a fluid present in a flow path, according to one or more
embodiments.
[0017] FIG. 6 is a flowchart of an exemplary process for real-time
flowback effluent analysis, according to one or more
embodiments.
DETAILED DESCRIPTION
[0018] The present invention relates to the separation of a
flowback effluent stream and, in particular, to systems and methods
for the real-time analysis of the composition of an input flowback
effluent stream or one or more separated output streams.
[0019] Separating a flowback effluent stream into secondary
streams, for example, a stream of liquid hydrocarbons or a stream
of gaseous hydrocarbons, presents an opportunity to market and sell
one or more of these secondary streams. Accordingly, it may be
advantageous to determine the composition of a particular secondary
stream, for example to verify that there is a minimum purity or
"quality" of the hydrocarbon content or to determine a price for
the delivered secondary stream. It may also be advantageous to
provide quantitative measurements of the amount of certain
materials in a secondary stream, for example the amount of
hydrocarbon remaining in a secondary stream of water, to verify
compliance with regulatory requirements. Continuous monitoring of
the composition of the multiple secondary streams exiting a
separator may also allow real-time verification of the performance
of the separation process.
[0020] The exemplary systems and methods described herein employ
various configurations of optical computing devices, also commonly
referred to as "opticoanalytical devices," for the real-time or
near real-time monitoring of fluids. In operation, the systems and
methods disclosed herein may be useful and otherwise advantageous
in determining the quality of a fluid in fluid separation
processes. For example, the optical computing devices disclosed
herein, which are described in more detail below, can
advantageously provide real-time or near real-time monitoring of
fluid separation processes that cannot presently be achieved with
either onsite analyses at a job site or via more detailed analyses
that take place in a laboratory. With real-time or near real-time
analyses on hand, the systems and methods described herein may be
able to provide some measure of proactive or responsive control
over the fluid separation processes, enable the collection and
archival of fluid information in conjunction with operational
information to optimize subsequent operations, and/or enhance the
capacity for remote job execution.
[0021] Those skilled in the art will readily appreciate that the
systems and methods disclosed herein may be suitable for use in the
oil and gas industry since the described optical computing devices
provide a cost-effective, rugged, and accurate means for monitoring
hydrocarbon quality in order to facilitate the efficient management
of oil/gas production. It will be appreciated, however, that the
various disclosed systems and methods are equally applicable to
other technology fields including, but not limited to, the food and
drug industry, industrial applications, mining industries, or any
field where it may be advantageous to determine the real-time
concentration or characteristic of a specific substance in a
flowing fluid, especially in separation applications. In at least
one embodiment, for example, the present systems and methods may be
employed to monitor the quality of potable water after the water
has undergone one or more separation processes to remove
contaminants or adulterants therefrom. In other embodiments, the
present systems and methods may be employed in the military or
security fields, such as in submarines or other water craft. In yet
other embodiments, the present systems and methods may prove useful
in the trucking and auto industries.
[0022] The optical computing devices suitable for use in the
present embodiments can be deployed at two or more fluidly
communicable points within a flow path, such as a fluid separation
device or separator. In some embodiments, for example, the optical
computing devices may be employed at both inlet and discharge
locations of a fluid separator in order to monitor the incoming and
outgoing fluids and, therefore, the overall effectiveness of the
separator device. In operation, the optical computing device
arranged at the discharge location may be configured to ensure a
proper or environmentally safe chemical composition of the fluid
upon its discharge from the separator. Depending on the location of
other optical computing devices, various types of information about
the fluid can be obtained. In some cases, for instance, the optical
computing devices can be used to monitor changes to the fluid as a
result of adding a treatment substance thereto, removing a
treatment substance therefrom in a separator, or exposing the fluid
to a condition that potentially changes a characteristic of the
fluid in some way.
[0023] As used herein, the term "oil" refers to a liquid mixture
that is composed primarily of hydrocarbons. Oil may include
residual amounts of liquid non-hydrocarbon materials and/or
dissolved gases.
[0024] As used herein, the term "water" refers to a liquid mixture
that is composed primarily of H.sub.2O. Water may include residual
amounts of liquid hydrocarbons and/or dissolved gases.
[0025] As used herein, the term "gas" refers to a mixture of one or
more materials in gas-phase form, with the primary component being
a gaseous hydrocarbon such as methane.
[0026] As used herein, the term "silt" refers to solid particles of
a size that the particles tend to remain in suspension during
conventional separation processes.
[0027] Within this document, the term "solids" refers to solid
particles of a size that the particles tend to drop out of
suspension during conventional separation processes.
[0028] As used herein, the term "fluid" refers to any substance
that is capable of flowing, including particulate solids, liquids,
gases, slurries, emulsions, powders, muds, glasses, mixtures,
combinations thereof, and the like. The fluid may be a single phase
or a multiphase fluid. In some embodiments, the fluid can be an
aqueous fluid, including water or the like. In other embodiments,
the fluid may be a non-aqueous fluid, including organic compounds,
more specifically, hydrocarbons, oil, a refined component of oil,
petrochemical products, and the like. In some embodiments, the
fluid can be a treatment fluid or a formation fluid as used in the
oil and gas industry. The fluid may also have one or more solids or
solid particulate substances entrained therein. For instance,
fluids can include various flowable mixtures of solids, liquids
and/or gases. Illustrative gases that can be considered fluids
according to the present embodiments, include, for example, air,
nitrogen, carbon dioxide, argon, helium, methane, ethane, butane,
and other hydrocarbon gases, combinations thereof, and/or the
like.
[0029] As used herein, the term "characteristic" refers to a
chemical, mechanical, or physical property of a substance or fluid,
such as a flowback effluent. A characteristic may also refer to a
chemical, mechanical, or physical property of a phase of a
substance or fluid. Illustrative characteristics of a substance
and/or a phase of the substance that can be detected or otherwise
monitored with the optical computing devices disclosed herein can
include, for example, chemical composition (e.g., identity and
concentration in total or of individual components), phase presence
and concentration, impurity content, pH, viscosity, density, ionic
strength, total dissolved solids, salt content, porosity, opacity,
bacteria content, combinations thereof, state of matter (i.e.,
solid, liquid, gas, emulsion, mixtures, etc.), and the like.
Exemplary characteristics of a phase of a substance, such as a
fluid, can include a volumetric flow rate of the phase, a mass flow
rate of the phase, or other properties of the phase derivable from
the volumetric and/or mass flow rate. Such properties can be
determined for each phase detected in the substance or fluid.
Moreover, the phrase "characteristic of interest of/in a fluid" may
be used herein to refer to the characteristic of a substance or a
phase of the substance contained in or otherwise flowing with the
fluid.
[0030] As used herein, the term "flow path" refers to a route
through which a fluid is capable of being transported between two
points. In some cases, the flow path need not be continuous or
otherwise contiguous between the two points. Exemplary flow paths
include, but are not limited to, a flowline, a pipeline, a
production tubular or tubing, an annulus defined between a wellbore
and a pipeline, a hose, a process facility, a storage vessel, a
separator, a tanker, a railway tank car, a transport ship or
vessel, a trough, a stream, a sewer, a subterranean formation,
combinations thereof, or the like. In cases where the flow path is
a pipeline, or the like, the pipeline may be a pre-commissioned
pipeline or an operational pipeline. In other cases, the flow path
may be created or generated via movement of an optical computing
device through a fluid (e.g., an open air sensor). In yet other
cases, the flow path is not necessarily contained within any rigid
structure, but refers to the path fluid takes between two points,
such as where a fluid flows from one location to another without
being contained, per se. It should be noted that the term "flow
path" does not necessarily imply that a fluid is flowing therein,
rather that a fluid is capable of being transported or otherwise
flowable therethrough.
[0031] As used herein, the term "phase" refers generally to a state
of matter of a substance or material. Exemplary phases include a
solid, a liquid (aqueous), a gas, or a plasma, but may also include
solid particulates or materials entrained or otherwise dissolved
within the liquid or gas phases. The term "phase," however, does
not necessarily imply or otherwise refer solely to state of matter,
since matter can exist in different phases at the same state of
matter. Instead, phase may also refer to a sufficiently homogeneous
or continuous geographical region of a substance or material that
exhibits a definable border or separation point with respect to
other adjacent homogeneous geographical regions. In other words, a
phase is a physically distinctive form of matter characterized by
having relatively uniform chemical and physical properties. For
example, two or more phases may exist in a purely liquid or fluid
state of matter, such as a liquid/liquid or gas/gas system.
Moreover, mixtures can exist in multiple phases, such as an oil
phase and an aqueous phase, or a gas saturated or otherwise
dissolved within an oil or an aqueous phase. Further, a gas phase
may have oil and water phases dispersed therein as fine globules.
In thermodynamically unstable systems, phase may further refer to
an emulsion or other finely divided solids trapped in either an oil
or aqueous phase.
[0032] As used herein, the term "substance," or variations thereof,
refers to at least a portion of a material of interest to be
evaluated using the optical computing devices described herein. In
some embodiments, the substance is the characteristic of interest,
as defined above, and may include any integral component or
chemical constituent of the fluid flowing within the flow path. In
other embodiments, the substance may be a material of interest
flowing jointly with and otherwise separate from the fluid.
[0033] As used herein, the term "electromagnetic radiation" refers
to radio waves, microwave radiation, infrared and near-infrared
radiation, visible light, ultraviolet light, X-ray radiation and
gamma ray radiation.
[0034] As used herein, the term "optical computing device" refers
to an optical device that is configured to receive an input of
electromagnetic radiation associated with a fluid, or a phase of
the fluid, and produce an output of electromagnetic radiation from
a processing element arranged within the optical computing device.
The processing element may be, for example, an integrated
computational element (ICE) used in the optical computing device.
The electromagnetic radiation that optically interacts with the
processing element is changed so as to be readable by a detector,
such that an output of the detector can be correlated to a
characteristic of the fluid or a phase of the fluid. The output of
electromagnetic radiation from the processing element can be
reflected electromagnetic radiation, transmitted electromagnetic
radiation, and/or dispersed electromagnetic radiation. Whether the
detector analyzes reflected, transmitted, or dispersed
electromagnetic radiation may be dictated by the structural
parameters of the optical computing device as well as other
considerations known to those skilled in the art. In addition,
emission and/or scattering of the fluid or a phase thereof, for
example via fluorescence, luminescence, Raman, Mie, and/or Raleigh
scattering, can also be monitored by the optical computing
devices.
[0035] As used herein, the term "optically interact" or variations
thereof refers to the reflection, transmission, scattering,
diffraction, or absorption of electromagnetic radiation either on,
through, or from one or more processing elements (i.e., integrated
computational elements), a fluid, or a phase of the fluid.
Accordingly, optically interacted light refers to electromagnetic
radiation that has been reflected, transmitted, scattered,
diffracted, or absorbed by, emitted, or re-radiated, for example,
using an integrated computational element, but may also apply to
interaction with a fluid or a phase of the fluid.
[0036] The exemplary systems and methods described herein may
include at least one optical computing device arranged along or in
a flow path in order to monitor a fluid flowing or otherwise
contained therein. Each optical computing device may include an
electromagnetic radiation source, at least one processing element
(e.g., an integrated computational element), and at least one
detector arranged to receive optically interacted light from the at
least one processing element or the fluid. In some embodiments, the
exemplary optical computing devices may be specifically configured
for detecting, analyzing, and quantitatively measuring a particular
characteristic of interest of the fluid or a phase of the fluid in
the flow path. In other embodiments, the optical computing devices
may be general purpose optical devices, with post-acquisition
processing (e.g., through computer means) being used to
specifically detect the characteristic of the fluid or phase of the
fluid.
[0037] In some embodiments, suitable structural components for the
exemplary optical computing devices are described in commonly owned
U.S. Pat. Nos. 6,198,531; 6,529,276; 7,123,844; 7,834,999;
7,911,605, 7,920,258, and 8,049,881, each of which is incorporated
herein by reference in its entirety, and U.S. patent application
Ser. Nos. 12/094,460; 12/094,465; and 13/456,467, each of which is
also incorporated herein by reference in its entirety. As will be
appreciated, variations of the structural components of the optical
computing devices described in the above-referenced patents and
patent applications may be suitable, without departing from the
scope of the disclosure, and therefore, should not be considered
limiting to the various embodiments or uses disclosed herein.
[0038] The optical computing devices described in the foregoing
patents and patent applications combine the advantage of the power,
precision and accuracy associated with laboratory spectrometers,
while being extremely rugged and suitable for field use.
Furthermore, the optical computing devices can perform calculations
(analyses) in real-time or near real-time without the need for
time-consuming sample processing. In this regard, the optical
computing devices can be specifically designed to detect and
analyze particular characteristics of interest of a fluid or a
phase of the fluid. As a result, interfering signals are
discriminated from those of interest in the fluid by appropriate
configuration of the optical computing devices, such that the
optical computing devices provide a rapid response regarding the
characteristics of the fluid as based on the detected output. In
some embodiments, the detected output can be converted into a
voltage that is distinctive of the magnitude of the characteristic
being monitored in the fluid.
[0039] The optical computing devices may be configured to detect as
many characteristics of interest as desired in the fluid. All that
is required to accomplish the monitoring of multiple
characteristics is the incorporation of suitable processing and
detection means within the optical computing device for each
characteristic of interest. In some embodiments, the properties of
the characteristic can be a combination of the properties of two or
more analytes present therein (e.g., a linear, non-linear,
logarithmic, and/or exponential combination). Accordingly, the more
characteristics and analytes that are detected and analyzed using
the optical computing devices, the more accurately the properties
of the given fluid or phase of the fluid will be determined.
[0040] The optical computing devices described herein utilize
electromagnetic radiation to perform calculations, as opposed to
the hardwired circuits of conventional electronic processors or
sensors. When electromagnetic radiation interacts with a fluid,
unique physical and chemical information about the fluid or a phase
within the fluid may be encoded in the electromagnetic radiation
that is reflected from, transmitted through, or radiated from the
fluid. This information is often referred to as the spectral
"fingerprint" of the fluid. The optical computing devices described
herein are capable of extracting the information of the spectral
fingerprint of multiple characteristics within a fluid, and
converting that information into a detectable output relating to
one or more properties of the fluid or a phase within the fluid.
That is, through suitable configurations of the optical computing
devices, electromagnetic radiation associated with a characteristic
of the fluid can be separated from electromagnetic radiation
associated with all other components of the fluid in order to
estimate the properties of the fluid or a phase within the fluid in
real-time or near real-time.
[0041] It may be particularly advantageous to utilize one or more
of these optical computing devices as part of a sensor assembly
configured to monitor one or more characteristics of a flowback
effluent stream as it is treated in a separator. In certain
embodiments, the optical computing device(s) forming part of the
sensor assembly may include an integrated computational element
(ICE) configured to monitor a particular characteristic that
identifies a substance that is part of the flowback effluent fluid.
In certain embodiments, the sensor assembly may also be configured
to monitor the flow rate of the flowback effluent stream. In
certain embodiments, the sensor assembly include an optical
computing device configured to monitor both the characteristic of
the substance and the flow rate.
[0042] For commercial or regulatory reasons, it may be advantageous
to determine the total amount of a secondary stream or of a single
substance of one or more of the secondary streams. For example,
measurement of a particular chemical may allow the documentation of
the total amount of that chemical discharged within a period of
time to show compliance with a regulatory requirement. A second
example may be the determination of the total quantity of methane
delivered to a customer in a secondary gas stream so as to prepare
an accurate deliverable pricing for that customer. In certain
embodiments, a measurement of a characteristic of a substance and a
measurement of a velocity of the flow that contains the substance
can be combined to provide a mass flow rate of the particular
substance, and monitoring of the characteristic and velocity at
least at periodic intervals over a period of time can be combined
with the intervals and the total period of time to provide a total
delivered mass of the substance.
[0043] FIG. 1 depicts an exemplary system 600 for the real-time
analysis and separation of a multiphase flowback effluent stream
620 according to certain aspects of the present disclosure. In this
example, a flowback effluent stream 620 is received from a
producing well 10 where, for example, a fracture stimulation
process may be underway. The flowback effluent stream 620 is
provided, in this example, to a four-phase, closed-loop separator
608, wherein the "closed-loop" descriptor indicates that the liquid
and gas secondary streams 630, 632, 640 are captured rather than
released or, in the case of the gas secondary stream, flared
off.
[0044] While shown in FIG. 1 as a four-phase separator device,
those skilled in the art will readily appreciated that the fluid
separator 608 may be any type of separator known to those skilled
in the art. For example, the illustrated separator 608 may be
configured to accept as an input the flowback effluent stream 620
and provide secondary streams 622, 624, 630, 632, and 640 of
solids, silt, water, oil, and gas, respectively. In other
embodiments, however, the separator 608 may be a three-phase
separator configured to separate the flowback effluent stream 620
into water, gas, and oil phases. Those skilled in the art will
readily appreciate that other numbers and types of secondary flows
may be provided, in certain embodiments, without departing from the
scope of the disclosure.
[0045] In operation, the separator 608 may be used to separate one
or more components in the flowback effluent stream 602 from one or
more other components present therein. For example, the fluid
separator 608 may include any type of separator used to separate
wellbore production fluids into their constituent components of,
for example, oil, gas, water, precipitates, impurities, condensates
(e.g., BTEX compounds), multiphase fluids, combinations thereof,
and the like. Suitable separators may include separators that
operate on the principle of density separation or separators that
operate on the principle of centrifugal separation. In operation, a
higher density material or substance (e.g., water) may be separated
from a lower density material or substance (e.g., gas, oil, etc.)
via differential settling or centrifuging, as known in the art. In
certain embodiments, the separator 608 may comprise, for example
and without limitation, oil and gas separators, stage separators,
trap separators, knockout vessels (knockout drum, knockout trap,
water knockout, or liquid knockout), flash chamber separators
(flash vessel or flash trap), expansion separator or expansion
vessel, scrubbers (gas scrubber), corrugated plate receptors,
filters (gas filter), cyclone technology (gas/solid separation,
hydrocyclones for liquid phase separation), and flocculent assisted
dissolved air and induced air flotation (DAF, IAF for solid and oil
separation for oily waste treatment). A separator 608, in certain
embodiments, may have portions configured as vertical or horizontal
process flows.
[0046] In some embodiments, various treatment chemicals, agents, or
substances, as known in the art, may be added to one or more of the
secondary streams 620, 623, 625, or 631 to help facilitate a more
efficient separation process. In certain embodiments, such
treatment substances may include, for example, emulsion breakers,
de-foaming agents, digester organisms, coalescing agents, and
flocculants. In certain embodiments, the relative concentrations of
such treatment substances can be monitored and measured using one
or more of the sensor assemblies 700, 710, 720, 730, 740, and 750
described below.
[0047] As illustrated, the separator 608 includes a solids
separator 610, an oil/water separator 614, and an oil/gas separator
616, thus producing the four output phases of solids, water, oil,
and gas, as secondary streams. In certain embodiments, the
separator 608 may further include a silt separator 612 configured
to remove fine suspended solids that may not have been removed by
the initial solids separator 610. The solids separator 610 allows
solids that are suspended in the effluent stream 620 to settle out
and be removed, for example, as a high-solids slurry in solids
secondary stream 622 that is directed into a solids holding tank
626. A cleaned effluent stream 623 is, in at least one embodiment,
directed to the silt separator 612 wherein the remaining silt (if
any) is filtered out of the effluent stream 623 and removed in a
silt secondary stream 624 directed into a silt holding tank 628. In
certain embodiments, the silt secondary stream 624 may be directed
into the solids holding tank 626. In certain embodiments, the
solids separation process is performed in a manifold or other
separation process (not shown in FIG. 1) prior to the cleaned
effluent stream 623 entering the separator 608.
[0048] The filtered effluent stream 625 may be directed to the
oil/water separator 614 which may remove the water from the oil and
gas and, in at least one embodiment, direct a water secondary
stream 630 to an injection well 20 where at least a portion of the
water stream 630 may be injected into a subterranean formation, for
example. A de-watered effluent stream 631 is directed to the
oil/gas separator 616 where the gas is removed from the oil. An oil
secondary stream 632 is directed, in this example, to a holding
tank 634 and a gas secondary stream 640 is directed, in this
example, to a storage tank 642. In certain embodiments, the gas
secondary stream 640 may be directed through a mass flow meter and
into a pipeline (not shown in FIG. 1) configured to transport the
gas secondary stream 640 to a remote location.
[0049] In the example system 600, various sensor assemblies 700,
710, 720, 730, 740, and 750 may be coupled to or otherwise arranged
within the secondary streams 620, 622, 624, 630, 632, and 640,
respectively. In certain embodiments, the system 600 may include a
reduced number of sensor assemblies coupled to one or more of the
lines for the streams 620, 622, 624, 630, 632, and 640. In certain
embodiments, each sensor assembly 700, 710, 720, 730, 740, and 750
may include at least one composition sensor and at least one fluid
properties sensor, which are discussed in greater detail below with
respect to FIG. 2. In some embodiments, one of more of the sensor
assemblies 700, 710, 720, 730, 740, and 750 may have only one
composition sensor or fluid properties sensor. In certain
embodiments, each sensor assembly 700, 710, 720, 730, 740, and 750
may be configured to detect identical characteristics of the
respective effluent flows. In other embodiments, however, one or
more of the sensor assemblies 700, 710, 720, 730, 740, and 750 may
be different from each other in terms of their sensing
capabilities. In certain embodiments, the composition sensors of
one or more of the sensor assemblies 700, 710, 720, 730, 740, and
750 may be configured to sense one or more substances in the
effluent stream from a particular source, for example the producing
well 10.
[0050] In certain embodiments, one or more sensor assemblies (not
shown in FIG. 1) that are similar to one of the sensor assemblies
700, 710, 720, 730, 740, and 750 may be coupled to one or more of
the internal effluent streams 623, 625, and 631. Comparison of the
measured characteristics of an internal effluent stream that is
immediately upstream of a separation process, for example the
filtered effluent stream 625 that is upstream of the oil/water
separator 614, to the measured characteristics of the two separated
streams, for example the water secondary stream 630 and the
de-watered effluent stream 631, may allow improved monitoring of
that particular separation process.
[0051] In certain embodiments, the oil secondary stream 632 may
contain a liquid hydrocarbon that may be sold to a customer. In
certain embodiments, the gas secondary stream 640 may contain a
gaseous hydrocarbon, for example methane, that may be sold to a
customer. One or both of the sensor assemblies 740 and 750 may
determine a purity or quality of the respective oil and gas
secondary streams 632, 640 and/or a quantity of oil and/or gas
delivered, as the price paid by the customer for the oil and/or gas
may depend on either the actual condition or verification of a
minimum condition of the oil and/or gas.
[0052] Referring now to FIG. 2, with continued reference to FIG. 1,
illustrated is a block diagram of an embodiment of a real-time
flowback effluent analysis system 800, according to certain aspects
of the present disclosure. The system 800 includes a processor 810
communicatively coupled to a user interface 814 that, in certain
embodiments, may include one or more of a display, a printer, a
user input device such as a mouse or keyboard, and a communication
port to an external system. The processor 810 may also be
communicatively coupled to a memory 812 that may be local or remote
and is configured to store programs and data. In certain
embodiments, the memory 812 may include one or more sequences of
instructions, programming stances, or code that configure the
processor 810 to perform various operations and functions.
[0053] The system 800 may also include the sensor assemblies 700,
710, 720, 730, 740, and 750 of FIG. 1. As illustrated, the sensor
assembly 700 may include an ICE sensor 702 and a multiphase fluid
parameter sensor 704. As will be discussed in greater detail below,
the ICE sensor 702 may be an optical computing device that employs
one or more integrated computational elements. In certain
embodiments, the ICE sensor 702 may be tuned or otherwise
configured to detect one or more characteristics of a substance
within the fluid being monitored, for example the flowback effluent
stream 620. Flowback effluent streams may include, for example, one
or more ions (e.g., monoatomic and/or polyatomic) such as, but not
limited to, HCO.sub.3.sup.-, Cl.sup.-, SO.sub.4.sup.2-, Na.sup.+,
Ca.sup.2+, Mg.sup.2+, Ba.sup.2+, Sr.sup.2+, and Fe.sup.3+ (total
Fe). Other chemical constituents that may be found in the flowback
effluent streams may include on or more of hydrochloric acid,
muriatic acid, glutaraldehyde, ammonium persulfate, N,n-dimethyl
formamide, borate salts, polyacrylamide, mineral oil, citric acid,
potassium chloride, ammonium bisulfate, sodium carbonate, potassium
carbonate, silica, quartz sand, ethylene glycol, isopropanol, guar
gum, hydroethyl cellulose, combinations thereof, and the like. In
operation, the ICE sensor 702 may be configured to particularly
sense one or more of these substances or chemical constituents. The
output of the ICE sensor 702 may comprise a composition of the
monitored flow or, in certain embodiments, may include measurements
made by the ICE sensor 702 and the determination of the composition
may be performed in the processor 810.
[0054] The multiphase fluid parameter sensor 704 may be configured,
in certain embodiments, to measure one or more characteristics of
the flowback effluent stream 620, such as velocity, mass flow rate,
and total mass discharge, within a period of time. In certain
embodiments, the parameter sensor 704 may comprise a densometer, or
the like. In certain embodiments, the parameter sensor 704 may
comprise a venture-type sensor. In certain embodiments, the
parameter sensor 704 may comprise one or more optical computing
devices employing one or more ICE elements configured to detect a
characteristic of interest in the fluid and otherwise measure a
flow velocity thereof. The combination of information about the
percentage composition of one or more substances within the stream,
characteristics such as density of the substances, and flow
velocity may provide a mass flow rate for one or more of the
component substances within the stream being monitored.
[0055] As illustrated, each sensor assembly 710, 720, 730, 740, and
750 may include at least one ICE sensor 712, 722, 732, 742, and
752, respectively, and may also include at least one parameter
sensor 714, 724, 734, 744, and 754, respectively. In certain
embodiments, the ICE sensors 712, 722, 732, 742, and 752 may be
configured to detect and measure the same substances as the ICE
sensor 702. In other embodiments, the ICE sensors 712, 722, 732,
742, and 752 may be configured to detect and measure only a subset
of the substances that are detected by the ICE sensor 702. In yet
other embodiments, the ICE sensors 712, 722, 732, 742, and 752 may
be configured to detect and measure substances that are not
detected by the ICE sensor 702. The processing elements (i.e.,
integrated computational elements or ICE components) used in the
optical computing devices of each ICE sensor 702 may be capable of
distinguishing electromagnetic radiation related to the
characteristic of interest from electromagnetic radiation related
to other components of a fluid.
[0056] Referring to FIG. 3, illustrated is an exemplary ICE 100
suitable for use in the optical computing devices used in the
sensor assemblies 700, 710, 720, 730, 740, and 750. As illustrated,
the ICE 100 may include a plurality of alternating layers 102 and
104, such as silicon (Si) and SiO.sub.2 (quartz), respectively. In
general, these layers 102, 104 consist of materials whose index of
refraction is high and low, respectively. Other examples might
include niobia and niobium, germanium and germania, MgF, SiO, and
other high and low index materials known in the art. The layers
102, 104 may be strategically deposited on an optical substrate
106. In some embodiments, the optical substrate 106 is BK-7 optical
glass. In other embodiments, the optical substrate 106 may be
another type of optical substrate, such as quartz, sapphire,
silicon, germanium, zinc selenide, zinc sulfide, or various
plastics such as polycarbonate, polymethylmethacrylate (PMMA),
polyvinylchloride (PVC), diamond, ceramics, combinations thereof,
and the like.
[0057] At the opposite end (e.g., opposite the optical substrate
106 in FIG. 3), the ICE 100 may include a layer 108 that is
generally exposed to the environment of the flow path, device, or
installation. The number of layers 102, 104 and the thickness of
each layer 102, 104 are determined from the spectral attributes
acquired from a spectroscopic analysis of a characteristic of the
substance using a conventional spectroscopic instrument. The
spectrum of interest of a given characteristic of a substance
typically includes any number of different wavelengths. It should
be understood that the exemplary ICE 100 in FIG. 3 does not, in
fact, represent any particular characteristic of a given substance,
but is provided for purposes of illustration only. Consequently,
the number of layers 102, 104 and their relative thicknesses, as
shown in FIG. 3, bear no correlation to any particular
characteristic of a given substance. Nor are the layers 102, 104
and their relative thicknesses necessarily drawn to scale, and
therefore should not be considered limiting of the present
disclosure. Moreover, those skilled in the art will readily
recognize that the materials that make up each layer 102, 104
(i.e., Si and SiO.sub.2) may vary, depending on the application,
cost of materials, and/or applicability of the material to the
substance.
[0058] In some embodiments, the material of each layer 102, 104 can
be doped or two or more materials can be combined in a manner to
achieve the desired optical characteristic. In addition to solids,
the exemplary ICE 100 may also contain liquids and/or gases,
optionally in combination with solids, in order to produce a
desired optical characteristic. In the case of gases and liquids,
the ICE 100 can contain a corresponding vessel (not shown), which
houses the gases or liquids. Exemplary variations of the ICE 100
may also include holographic optical elements, gratings,
piezoelectric, light pipe, digital light processing (DLP), and/or
acousto-optic elements, for example, that can create transmission,
reflection, and/or absorptive properties of interest.
[0059] The multiple layers 102, 104 exhibit different refractive
indices. By properly selecting the materials of the layers 102, 104
and their relative thickness and spacing, the ICE 100 may be
configured to selectively pass/reflect/refract predetermined
fractions of electromagnetic radiation at different wavelengths.
Each wavelength is given a predetermined weighting or loading
factor. The thickness and spacing of the layers 102, 104 may be
determined using a variety of approximation methods from the
spectrograph of the characteristic or analyte of interest. These
methods may include inverse Fourier transform (IFT) of the optical
transmission spectrum and structuring the ICE 100 as the physical
representation of the IFT. The approximations convert the IFT into
a structure based on known materials with constant refractive
indices. Further information regarding the structures and design of
exemplary integrated computational elements (also referred to as
multivariate optical elements) is provided in Applied Optics, Vol.
35, pp. 5484-5492 (1996) and Vol. 29, pp. 2876-2893 (1990), which
are hereby incorporated by reference.
[0060] The weightings that the layers 102, 104 of the ICE 100 apply
at each wavelength are set to the regression weightings described
with respect to a known equation, or data, or spectral signature.
Briefly, the ICE 100 may be configured to perform the dot product
of the input light beam into the ICE100 and a desired loaded
regression vector represented by each layer 102, 104 for each
wavelength. As a result, the output light intensity of the ICE 100
is related to the characteristic or analyte of interest. Further
details regarding how the exemplary ICE 100 is able to distinguish
and process electromagnetic radiation related to the characteristic
or analyte of interest are described in U.S. Pat. Nos. 6,198,531;
6,529,276; and 7,920,258, previously incorporated herein by
reference.
[0061] Referring now to FIG. 4, illustrated is an exemplary
measurement system 200 for monitoring a fluid 202, according to one
or more embodiments. In the illustrated embodiment, the fluid 202
may be contained or otherwise flowing within an exemplary flow path
204. The flow path 204 may be a flow line or a pipeline and the
fluid 202 present therein may be flowing in the general direction
indicated by the arrows A (i.e., from upstream to downstream). In
some embodiments, the flow path 204 may be associated with a
separator device, such as the four-phase separator 608 of FIG. 1,
and the fluid 202 may be the flowback effluent stream 620. As will
be appreciated, however, the flow path 204 may be any other type of
flow path, as generally described or otherwise defined herein.
Portions of the flow path 204 may be arranged substantially
vertical, substantially horizontal, or any directional
configuration therebetween, without departing from the scope of the
disclosure.
[0062] The measurement system 200 may include an optical computing
device 206 configured to determine a characteristic of interest in
the fluid 202 or a phase of the fluid 202 as contained within the
flow path 204. In some embodiments, the optical computing device
206 (or variations thereof) may be the optical computing device
used in one or more of the sensor assemblies 700, 710, 720, 730,
740, and 750, as described above. As illustrated, the device 206
may include an electromagnetic radiation source 208 configured to
emit or otherwise generate electromagnetic radiation 210. The
electromagnetic radiation source 208 may be any device capable of
emitting or generating electromagnetic radiation, as defined
herein. For example, the electromagnetic radiation source 208 may
be a light bulb, a light-emitting diode (LED), a laser, a
blackbody, a photonic crystal, an x-ray source, combinations
thereof, or the like. In some embodiments, a lens (not shown), or
any other type of optical device configured to transmit or
otherwise convey electromagnetic radiation, may be arranged to
collect or otherwise receive the electromagnetic radiation 210 and
direct a beam of the same toward the fluid 202.
[0063] In one or more embodiments, the optical computing device 206
may be configured to transmit the electromagnetic radiation 210
through the fluid 202 via a first sampling window 212a and a second
sampling window 212b arranged radially-opposite the first sampling
window 212a on the flow path 204. One or both of the sampling
windows 212a,b may be made from a variety of transparent, rigid or
semi-rigid materials that are configured to allow transmission of
the electromagnetic radiation 210 therethrough. For example, the
sampling windows 212a,b may be made of, but is not limited to,
glasses, plastics, semi-conductors, sapphires, crystalline
materials, polycrystalline materials, hot or cold-pressed powders,
combinations thereof, or the like.
[0064] As the electromagnetic radiation 210 passes through the
fluid 202 via the first and second sampling windows 212a,b, it
optically interacts with the fluid 202. Optically interacted
radiation 214 is thereby generated and subsequently directed to or
otherwise received by one or more ICE 216 arranged within the
optical computing device 206, such as a first ICE 216a, a second
ICE 216b, a third ICE 216c, and one or more additional ICE 216n.
While only four ICE 216a-n are depicted, more or less could be
employed, without departing from the scope of the disclosure. As
illustrated, the ICE 216a-n may be arranged in parallel within the
optical computing device 206 and a series of beam splitters 218a,
218b, 218c, 218n may be used to separate or otherwise redirect the
optically interacted radiation 214 such that a respective beam
220a, 220b, 220c, 220n of optically interacted radiation 214 is
directed toward a corresponding ICE 216a-n. Those skilled in the
art will readily recognize that alternative configurations of the
device 206 may allow the optically interacted radiation 214 to be
generated by being scattered, diffracted, absorbed, emitted, or
re-radiated by and/or from the fluid 202, without departing from
the scope of the disclosure.
[0065] Each ICE 216a-n may be a spectral component substantially
similar to the ICE 100 described above with reference to FIG. 3.
Accordingly, in operation each ICE 216a-n may be configured to
receive a portion of the optically interacted radiation 214 and
produce modified electromagnetic radiation or optically interacted
light 222a-n corresponding to a particular characteristic of
interest of the fluid 202. As defined above, the optically
interacted light 222a-n is electromagnetic radiation that has
optically interacted with the ICE 216a-n, whereby an approximate
mimicking of the regression vector corresponding to the
characteristic of interest of the fluid 202 is obtained.
[0066] Each ICE 216a-n may then be configured to transmit its
respective optically interacted light 222a-n toward a corresponding
detector 224a-n for quantification of the signal. Each detector
224a-n may be any device capable of detecting electromagnetic
radiation, and may be generally characterized as an optical
transducer. In some embodiments, the detectors 224a-n may be, but
are not limited to, a thermal detector such as a thermopile or
photoacoustic detector, a semiconductor detector, a piezo-electric
detector, a charge coupled device (CCD) detector, a video or array
detector, a split detector, a photon detector (such as a
photomultiplier tube), photodiodes, combinations thereof, or the
like, or other detectors known to those skilled in the art.
[0067] Each detector 224a-n may be configured to produce an output
signal in real-time or near real-time in the form of a voltage (or
current) that corresponds to the particular characteristic of
interest in the fluid 202. For example, each detector 224a-n may
generate or otherwise transmit first, second, third, and additional
output signals 226a, 226b, 226c, and 226n, respectively. The
voltage returned by each detector 224a-n is essentially the dot
product of the optical interaction of the optically interacted
radiation 214 with the respective ICE 216a-n as a function of the
concentration of the characteristic of interest of the fluid 202.
As such, each output signal 226a-n produced by its corresponding
detector 224a-n and the concentration of the characteristic of
interest in the fluid 202 may be related.
[0068] The output signals 226a-n may then be received by a signal
processor 228 communicably coupled to each detector 224a-n. In
certain embodiments, the processor 810 of the flowback effluent
analysis system 800 of FIG. 2 may include a signal processor 228.
The signal processor 228 may be a computer including a processor
and a machine-readable storage medium having instructions stored
thereon, which, when executed by the processor, cause the optical
computing device 206 to perform a number of operations, such as
determining a characteristic of interest of the fluid 202 or a
phase of the fluid 202. In real-time or near real-time, the signal
processor 228 may be configured to provide a resulting output
signal 230 corresponding to one or more characteristics of the
fluid 202 or a phase of the fluid 202. In some embodiments, the
resulting output signal 230 may be conveyed, either wired or
wirelessly, to an operator for consideration. In other embodiments,
the resulting output signal 230 may be recognized by the signal
processor 228 as being within or without a predetermined or
preprogrammed range of suitable operation. If the resulting output
signal 230 exceeds the predetermined or preprogrammed range of
operation, the signal processor 228 may be configured to alert the
operator so appropriate corrective action may be taken, or
otherwise autonomously undertake the appropriate corrective action
such that the resulting output signal 230 returns to a value within
the predetermined or preprogrammed range of operation.
[0069] In exemplary operation, each ICE 216a-n may be configured to
detect a different characteristic of the fluid 202 or phase of the
fluid 202. As a result, each output signal 226a-n may be different,
and the resulting output signal 230 may provide an operator with
several pieces of valuable data regarding the fluid 202 within the
flow path 204. One exemplary characteristic that may be monitored
by the device 206 includes the specific states of matter present
within the fluid. Another exemplary characteristic that may be
determined with the device 206 is the particular phases of the
fluid 202 (e.g., water, gas, oil, etc.). For instance, the first
ICE 216a may be configured to detect an aqueous phase in the fluid
202, the second ICE 216b may be configured to detect a gas phase in
the fluid 202, and the third ICE 216c may be configured to detect
an oil phase in the fluid 202. As a result, the device 206 may be
able to provide the operator with data regarding which phases are
present within the fluid 202 and their respective concentrations.
In other embodiments, a single ICE 216a-c may be employed to detect
more than one phase characteristic of the fluid 202. For example,
one or more of the ICE 216a-c may be used to detect the
concentration of methane, and simultaneously determine its state of
matter, e.g., gas, solid, liquid, or a mixture/combination
thereof.
[0070] Other characteristics of the fluid 202 or a phase of the
fluid 202 that may be detected with the device 206 include, but are
not limited to, salt content, methane concentration, sand or other
particulate concentration, hydrogen sulfide (H.sub.2S)
concentration, scale and/or hydrates (e.g., calcium carbonate)
concentration, various ions of interest such as, but not limited
to, Al.sup.+, B.sup.+, Ba.sub.2.sup.+, Sr.sub.2.sup.+, Fe.sup.+,
Fe.sub.2.sup.+ (or total Fe), I.sup.+, Mn.sub.2.sup.+,
SO.sub.4.sup.2-, CO.sub.3.sup.2-, Ca.sub.2.sup.+, Mg.sub.2.sup.+,
Mn.sup.+, Na.sup.+, K.sup.+, Cl.sup.-, Sr.sup.+, Zn.sup.+,
sulfates, sulfides, carbonates, oxides, fluid states of matter
(e.g., gas, solid, liquid, and mixtures or associated compositions
thereof), total dissolved solids, total suspended solids, pH,
density, combinations thereof, and the like. Accordingly, the
signal processor 228 may be configured to receive the various
output signals 226a-n and provide the operator with one or more
characteristics of the fluid 202 and/or the phase(s) of the fluid
202 in the form of the resulting output signal 230.
[0071] Referring now to FIG. 5, with continued reference to FIG. 4,
illustrated is another exemplary measurement system 300 for
monitoring the fluid 202, according to one or more embodiments.
Similar to the measurement system 200 of FIG. 4, the measurement
system 300 may be configured to monitor the fluid 202 contained or
otherwise flowing within an exemplary flow path 204 and determine a
particular characteristic of the fluid 202 within the flow path
204, such as determining a phase or state of matter of the fluid
202, or a concentration of a characteristic or phase that may be
present within the fluid 202. Moreover, the measurement system 300,
and its described optical computing devices, may be used in
conjunction with one or more of the sensor assemblies 700, 710,
720, 730, 740, and 750, as described above.
[0072] As illustrated, the measurement system 300 may include at
least a first optical computing device 206a and a second optical
computing device 206b. The first and second optical computing
devices 206a,b may be similar in some respects to the optical
computing device 206 of FIG. 4, and therefore may be best
understood with reference thereto where like numerals represent
like elements not described again in detail. As illustrated, the
first and second optical computing devices 206a,b may each be
associated with the flow path 204 at independent and distinct
monitoring locations along the length thereof. Specifically, the
first optical computing device 206a may be located at a first
monitoring location and the second optical computing device 206b
may be located at a second monitoring location, where the first
monitoring location fluidly communicates with the second monitoring
location via contiguous portions of the flow path 204.
[0073] In some embodiments, the second optical computing device
206b is arranged at a predetermined distance from the first optical
computing device 206a along the length of the flow path 204. In
other embodiments, however, the first optical computing device 206a
may be randomly spaced from the second optical computing device
206b, without departing from the scope of the disclosure. Moreover,
while two optical computing devices 206a,b are shown in FIG. 5, it
will be appreciated that the measurement system 300 may employ any
number of optical computing devices (including one) within the flow
path 204 and equally determine the characteristic of the fluid 202
or a phase of the fluid 202. In such embodiments, each additional
optical computing device may be spaced from the first and second
optical computing devices 206a,b at predetermined or random
distances, depending on the application.
[0074] Each device 206a,b may be housed within an individual casing
or housing coupled or otherwise attached to the flow path 204 at
its respective location. As illustrated, for example, the first
device 206a may be housed within a first housing 302a and the
second device 206b may be housed within a second housing 302b.
[0075] In some embodiments, each device 206a,b may include the
electromagnetic radiation source 208 configured to emit or
otherwise generate electromagnetic radiation 210. In one or more
embodiments, each device 206a,b may also include a sampling window
304 arranged adjacent the fluid 202 for detection purposes. The
sampling window 304 may be similar to the sampling windows 212a,b
of FIG. 4 and made from a variety of transparent, rigid or
semi-rigid materials that are configured to allow transmission of
the electromagnetic radiation 210 therethrough. After passing
through the sampling window 304, the electromagnetic radiation 210
impinges upon and optically interacts with the fluid 202. As a
result, optically interacted radiation 214 is generated by and
otherwise reflected from the fluid 202. Those skilled in the art,
however, will readily recognize that alternative variations of the
devices 206a,b may allow the optically interacted radiation 214 to
be generated by being transmitted through, scattered, diffracted,
absorbed, emitted, or re-radiated (e.g., via fluorescence or
phosphorescence methods) by and/or from the fluid 202, without
departing from the scope of the disclosure.
[0076] The optically interacted radiation 214 of each device 206a,b
may be directed to or otherwise be received by an ICE 216 arranged
within each corresponding device 206a,b. Each ICE 216 may be
configured to receive the optically interacted radiation 214 and
produce modified electromagnetic radiation or optically interacted
light 222 corresponding to a particular characteristic of interest
of the fluid 202 or a phase of the fluid 202.
[0077] It should be noted that, while FIG. 5 depicts the ICE 216 as
receiving reflected electromagnetic radiation from the fluid 202,
the ICE 216 may be arranged at any point along the optical train of
the device 206a,b, without departing from the scope of the
disclosure. For example, in one or more embodiments, the ICE 216
may be arranged within the optical train prior to the sampling
window 304 and the optical computing device 206a,b will obtain
substantially the same results. In other embodiments, the sampling
window 304 may serve a dual purpose as both a transmission window
and the ICE 216 (i.e., a spectral component). In yet other
embodiments, the ICE 216 may generate the optically interacted
radiation 222 through reflection, instead of transmission
therethrough.
[0078] Moreover, while only one ICE 216 is shown in each
corresponding device 206a,b, similar to the optical computing
device 206 of FIG. 4, embodiments are contemplated herein which
include the use of two or more ICE 216 in each device 206a,b, each
being configured to detect a different characteristic of the fluid
202 or phase of the fluid 202. In some embodiments, it may be
desirable to monitor more than one characteristic of the fluid 202
at a time at each location along the flow path 204. In such
embodiments, various configurations of multiple ICE 216 can be used
in a single optical computing device 206a,b, where each ICE 216 is
configured or otherwise designed to detect a particular and/or
distinct characteristic of interest in the fluid 202. For example,
as illustrated and discussed in FIG. 4, two or more ICE 216 may be
arranged in series or parallel within each device 206a,b and each
ICE 216 may be configured to detect a different characteristic of
the fluid 202, a different phase of the fluid 202, and/or a
different characteristic of a phase of the fluid 202. In such
embodiments, one or more beam splitters may be used to divert a
portion of the electromagnetic radiation being reflected by,
emitted from, or transmitted through the fluid 202 and so that it
may optically interact with each ICE 216.
[0079] The optically interacted light 222 generated by each ICE 216
may subsequently be conveyed to a detector 224 for quantification
of the signal. The detector 224 in each device 206a,b may be
configured to produce an output signal in real-time or near
real-time in the form of a voltage (or current) that corresponds to
the particular characteristic of interest in the fluid 202 or a
phase of the fluid 202. For example, the detector 224 arranged
within the first device 206a may generate a first output signal
226a, and the detector 224 arranged within the second device 206b
may generate a second output signal 226b. The output signal 226a,b
from each device 206a,b may be conveyed to or otherwise received by
the signal processor 228. In some embodiments, the signal processor
228 may be configured to compute or otherwise identify one or more
characteristics of interest of the fluid 202. In other embodiments,
the signal processor 228 may be configured to compute or otherwise
identify one or more phases present within the fluid 202. In yet
other embodiments, the signal processor 228 may be configured to
compute or otherwise identify one or more characteristics of a
phase present within the fluid 202. In at least one embodiment, the
first and second output signals 226a,b may be indicative of
characteristics of the fluid 202, such as, but not limited to, pH,
viscosity, density or specific gravity, and ionic strength, as
measured at the first and second monitoring locations,
respectively.
[0080] In at least one embodiment, the signal processor 228 may be
configured to perform an autocorrelation operation on the collected
output signals 226a,b in order to determine a characteristic of a
phase of the fluid 202. In particular, for example, the
autocorrelation operation may be undertaken such that a factor of
fluctuation per unit time is matched to each respective phase of
the fluid 202. The signal processor 228 may perform a number of
operations, such as determining a characteristic of a phase of the
fluid 202 based on results from performing the autocorrelation
operation. Exemplary characteristics determined based on results
from performing the autocorrelation operation include, but are not
limited to, a volumetric flow rate of the phase, a mass flow rate
of the phase, flow regime (e.g., turbulent or laminar, or
combinations thereof) or other characteristics of the phase
derivable from the volumetric and/or mass flow rate. The
autocorrelation operation on the collected output signals 226a,b
may employ one or more techniques such as, but not limited to, time
evolved factor analysis, general autocorrelation, coherence and
partial coherence methods, multivariate curve resolution, histogram
profiling, or other similar evaluation process.
[0081] In some embodiments, a fluid stream perturbing device 229
may be operatively arranged within the flow path 204 upstream from
the first and second optical computing devices 206a,b. With the
autocorrelation operation based on variations or fluctuations in
the phases of the fluid 202 over time, phases that are consistent
over distance or mildly grading in composition and properties may
be insensitive to the autocorrelation technique for determining
flow rates of the phases. The fluid stream perturbing device 229
may be configured to inject a perturbation upstream of the optical
computing devices 206a,b relative to a phase of the fluid 202, when
the phase is flowing without sufficient variation at the respective
measuring points absent the perturbation. Those skilled in the art
will readily recognize that natural perturbing instances may occur
in the flow path 204 such that use of the fluid stream perturbing
device 229 may be reduced or eliminated altogether in some
embodiments.
[0082] The arrangement of the optical computing devices 206a,b and
the evaluation of their measurements may be configured to use
perturbation(s) that is/are observable by the such devices 206a,b.
For instance, a perturbation may be induction of a gas bubble, a
change from laminar flow to turbulent flow, or injection of an
absorbing or fluorescing dye. A single perturbation most likely
affects different phases differently. However, in the case that a
perturbation does not affect a given phase at all, multiple
perturbations (one for each independent phase) may be induced.
Relative perturbations may be induced in the case that an absolute
perturbation provides less than sufficient delineating
characterization. For instance, two dies may simultaneously be
injected in different concentrations to induce a relative optical
density ratio between two different optical band centers.
Perturbations may also be varied temporally with characteristic
frequencies, beats, or cords so as to lock the pattern.
[0083] With a known distance between the first and second optical
computing devices 206a,b, and/or the perturbation point, the
autocorrelation function using the output signals 226a,b may yield
a linear velocity for each phase observed within the fluid 202.
This autocorrelation function may make use of various algorithms to
perform the autocorrelation operation. Such autocorrelation
algorithms may include, but are not limited to, time evolved factor
analysis, general autocorrelation, multivariate curve resolution,
coherence or partial coherence methods, or histogram profiling.
Such algorithms can be part of an artificial neural network
configured to use the concentration of each detected characteristic
in order to evaluate the overall characteristic(s) of the fluid
202. Illustrative but non-limiting artificial neural networks are
described in commonly owned U.S. patent application Ser. No.
11/986,763 (U.S. Patent App. Pub. No. 2009/0182693), which is
incorporated herein by reference.
[0084] It is to be recognized that an artificial neural network can
be trained using samples of fluids 202 having known
characteristics, phases, concentrations, compositions, and/or
properties, and thereby generating a virtual library. As the
virtual library available to the artificial neural network becomes
larger, the neural network can become more capable of accurately
predicting the characteristics of the fluid 202 and any phases
present therein. Furthermore, with sufficient training, the
artificial neural network can more accurately predict the
characteristics of the fluid 202, even in the presence of unknown
characteristics or phases.
[0085] To convert the linear flow provided by the autocorrelation
analysis of the data received from the output signals 226a,b into
volumetric flow, the fluid phase cross section can be determined at
the location of each optical computing device 206a,b. For instance,
an average phase volume, determined for the regions near each
optical computing device 206a,b, can be determined using each
optical computing device 206a,b. Alternatively, the optical
computing devices 206a,b may configured to detect and determine
mass flow of each detected phase. Mass flow and volumetric flow may
be interconverted with known phase densities (e.g., densities for
water, gases, and oils). Alternatively, if mass flow and volumetric
flow are determined, then phase densities may be calculated. In
addition, phase compressibility may be derived from the optical
computing devices 206a,b if located at points of differing
pressures within the flow path 204, or from flow velocities
correlated over differing pressures, if phase velocities are
known.
[0086] Accordingly, the autocorrelation operations of the signal
processor 228 provide a mechanism to look at variations in the
fluid 202 across the optical computing devices 206a,b. As briefly
mentioned above, one example of an autocorrelation operation can be
realized by applying a time evolved factor analysis where each
optical computing device 206a,b can be considered to be a different
channel. An auto correlation function provided by the time evolved
factor analysis provides a technique designed to match factors with
factors of fluctuation across unit time. In such a system, a number
of different factors may be determined, for example, two different
factors or three different factors, where each factor is equivalent
to the number of phases of the fluid 202. The factor fluctuation
per unit time can yield a flow rate for these different phases. If
the distance between the optical computing devices 206a,b is known,
such a flow rate can be calculated as a volumetric flow rate.
Moreover, with known densities of the composition of the fluid 202,
the factor fluctuation per unit time can yield a flow rate that
translates to mass. In such an analysis, the number of optical
computing devices 206a,b dispersed throughout the system 300 may be
configured such that they are sensitive to the different phases in
the fluid 202. As will be appreciated, a combination of optical
computing devices 206a,b, which yield enough degrees of freedom to
physically provide the data for the different phases, can be used
such that each optical computing device 206a,b need not be
sensitive to all phases.
[0087] In real-time or near real-time, the signal processor 228 may
be configured to provide a resulting output signal 230
corresponding to the characteristic of the fluid 202 or a phase of
the fluid 202 based on the results from the autocorrelation
operation. In some embodiments, the resulting output signal 230 may
be conveyed, either wired or wirelessly, to an operator for
consideration. In other embodiments, the resulting output signal
230 may be recognized by the signal processor 228 as being within
or without a predetermined or preprogrammed range of suitable
operation. If the resulting output signal 230 exceeds the
predetermined or preprogrammed range of operation, the signal
processor 228 may be configured to alert the operator so
appropriate corrective action may be taken, or otherwise
autonomously undertake the appropriate corrective action such that
the resulting output signal 230 returns to a value within the
predetermined or preprogrammed range of operation.
[0088] Still referring to FIG. 5, in other embodiments, one of the
optical computing devices 206a,b may be omitted from the system
300, such as the first optical computing device 206a, and an
optical light pipe 306 may be included to facilitate the monitoring
and/or detection of the fluid 202 at or near the first monitoring
location. In alternative embodiments, it will be appreciated that
the second optical computing device 206b may instead be omitted and
the optical light pipe 306 may be used to monitor the fluid 202 at
or near the second monitoring location, and equally obtain the same
results.
[0089] The optical light pipe 306 may be a fiber optic lead, probe,
or conduit used for the transmission of electromagnetic radiation
to/from the second optical computing device 206b. The optical light
pipe 306 may communicably couple the second optical computing
device 206b to the fluid 202 at or near the first monitoring
location. For example, the optical light pipe 306 may be configured
to convey electromagnetic radiation from the second optical
computing device 206b to the fluid 202 for the purpose of
determining the particular characteristic of the fluid 202 or a
phase of the fluid 202. The optical light pipe 306 may also be
configured to convey optically interacted radiation from the fluid
202 back to the second optical computing device 206b.
[0090] In exemplary operation, the second optical computing device
206b may receive optically interacted radiation from the fluid 202
at both the first and second monitoring locations. The detector 224
arranged within the second optical computing device 206b may be
configured to time multiplex the dual beams of optically interacted
light from the fluid 202 derived from each monitoring location. For
example, the optically interacted radiation received via the
optical light pipe 306 at the first monitoring location may be
directed to or otherwise received by the second optical computing
device 206b at a first time T1, and the optically interacted
radiation derived at the second monitoring location may be directed
to or otherwise received by the second optical computing device
206b at a second time T2, where the first and second times T1, T2
are distinct time periods that do not spatially overlap.
[0091] Consequently, the detector 224 receives at least two
distinct beams of optically interacted light from the ICE 216 and
is able to convey corresponding output signals 226b for the
respective beams to the signal processor 228 for processing. The
first beam of optically interacted light may indicate a
characteristic of the fluid 202 at the first monitoring location,
while the second beam of optically interacted light may indicate
the characteristic of the fluid 202 at the second monitoring
location. By employing one or more autocorrelation operations as
discussed herein above, the signal processor 228 may be able to
determine particular phase characteristics of the fluid 202, such
as volumetric and mass flow rates, flow regimes (e.g., turbulent or
laminar, or combinations thereof), or other characteristics of the
phase(s) derivable from the volumetric and/or mass flow rate.
[0092] FIG. 6 is a flowchart of an exemplary process 900 for
real-time flowback effluent analysis, according to certain aspects
of the present disclosure. The process 900 simultaneously measures
a characteristic of a fluid stream (e.g., a flowback effluent
stream), as at 910, and one or more fluid parameters of the fluid
stream, as at 915. In some embodiments, the characteristic of the
fluid stream may be measured with a sensor that includes one or
more ICE components as used within an optical computing device, as
generally described above. The process 900 then proceeds to
determine a concentration of a substance in the fluid, as at 920,
using the detected characteristic of the fluid stream. In one or
more embodiments, the concentration of the substance determined may
include a volume percentage of the particular substance.
[0093] In certain embodiments, the measurement of the one or more
fluid parameters of the fluid stream may include the detection of a
characteristic of the fluid. For example, the characteristic of the
fluid may be an increase in a concentration of a substance which
may be determined using a first ICE at a first time at a first
point along the fluid stream. The detection of the same
characteristic of the fluid may be determined using a second ICE at
a second time at a second point along the fluid stream, where the
first and second points are separated by a known distance. In
certain embodiments the measurement of the one or more fluid
parameters of the fluid stream may further include a determination
of a velocity of the fluid stream by dividing the distance between
the first and second points by the elapsed time between the first
and second times.
[0094] The process 900 may further include determining a mass flow
rate of the fluid stream, as at 925. In some embodiments, this may
be accomplished by multiplying the density of the fluid by the
velocity of the fluid. In certain embodiments, the density may also
be determined using, for example, a densometer. Once the mass flow
rate of the fluid stream and the concentration of the substance in
the fluid stream are known, the mass flow rate of the substance may
be determined, as at 930, for example by multiplying the mass flow
rate of the fluid stream by the concentration of the substance. In
certain embodiments, it is desirable to determine the total mass of
the substance delivered within a period of time, as at 940. This
may be accomplished, for example, by integrating the mass flow rate
of the substance over the period of time. This may be beneficial
if, for example, one or more of the oil and gas secondary streams
632, 640 of FIG. 1 are being sold and it is determine the amount
delivered within a period of time, such as a month. Some or all of
the measurements, calculations, and determinations are stored, as
at 950, for example, in the memory 812 shown in FIG. 2 or sent to
an external memory through the user interface 814.
[0095] In summary, the disclosed system and methods of measuring
one or more characteristics, such as the concentrations, of one or
more substances in a multiphase flowback effluent stream,
separating the effluent stream into secondary streams that include
one or more of a solids secondary stream, a silt secondary stream,
a water secondary stream, an oil secondary stream, and a gas
secondary stream may allow one or more of the separated secondary
streams to be sold, wherein the real-time monitoring may verify
compliance with quality requirements of the customer. The measured
characteristics can also be used to determine a velocity or a mass
flow rate of either the substance or the entire stream. The
collected information regarding composition of the various effluent
streams may demonstrate compliance with regulatory requirements as
well as monitor the performance of the separation processes.
Sensors comprising one or more ICEs are particularly suited for
determining one or both of the concentration of substances within
the flowback effluent and the individual secondary output streams
and the velocities of the same streams.
[0096] Therefore, the present invention is well adapted to attain
the ends and advantages mentioned as well as those that are
inherent therein. The particular embodiments disclosed above are
illustrative only, as the present invention may be modified and
practiced in different but equivalent manners apparent to those
skilled in the art having the benefit of the teachings herein.
Furthermore, no limitations are intended to the details of
construction or design herein shown, other than as described in the
claims below. It is therefore evident that the particular
illustrative embodiments disclosed above may be altered, combined,
or modified and all such variations are considered within the scope
and spirit of the present invention. The invention illustratively
disclosed herein suitably may be practiced in the absence of any
element that is not specifically disclosed herein and/or any
optional element disclosed herein.
[0097] It is recognized that the various embodiments herein
directed to computer control and artificial neural networks,
including various blocks, modules, elements, components, methods,
and algorithms, can be implemented using computer hardware,
software, combinations thereof, and the like. To illustrate this
interchangeability of hardware and software, various illustrative
blocks, modules, elements, components, methods and algorithms have
been described generally in terms of their functionality. Whether
such functionality is implemented as hardware or software will
depend upon the particular application and any imposed design
constraints. For at least this reason, it is to be recognized that
one of ordinary skill in the art can implement the described
functionality in a variety of ways for a particular application.
Further, various components and blocks can be arranged in a
different order or partitioned differently, for example, without
departing from the scope of the embodiments expressly
described.
[0098] Computer hardware used to implement the processor 810
described herein can include a general purpose microprocessor, a
microcontroller, a digital signal processor, an application
specific integrated circuit, a field programmable gate array, a
programmable logic device, a controller, a state machine, a gated
logic, discrete hardware components, an artificial neural network,
or any like suitable entity that can perform calculations or other
manipulations of data. In some embodiments, the memory 812 may be a
random-access memory (RAM), a flash memory, a read-only memory
(ROM), a programmable read-only memory (PROM), an erasable
read-only memory (EPROM), a register, a hard disk, a removable
disk, a read-only compact disk (CD-ROM), a DVD, or any other
suitable storage device or medium.
[0099] Executable sequences described herein can be implemented
with one or more sequences of code contained in a memory. In some
embodiments, such code can be read into the memory from another
machine-readable medium. Execution of the sequences of instructions
contained in the memory can cause a processor to perform the
process steps described herein. One or more processors in a
multi-processing arrangement can also be employed to execute
instruction sequences in the memory. In addition, hard-wired
circuitry can be used in place of or in combination with software
instructions to implement various embodiments described herein.
Thus, the present embodiments are not limited to any specific
combination of hardware and/or software.
[0100] As used herein, a non-volatile, machine-readable medium will
refer to any medium that stores instructions that, when provided to
a processor for execution, configure the processor to perform a
function, wherein the instructions are not lost upon removal or
electrical power from the medium. Non-volatile media includes, for
example, magnetically encodable media such as a floppy disk, a
magnetic hard disk, a flexible magnetic tape and other like
magnetic media, optically encodable media such as a CD-ROM, a
rewritable CD, an optical hard disk, and other like optical media,
and devices such as a PROM, an EPROM and a flash EPROM.
[0101] While compositions and methods are described in terms of
"comprising," "containing," or "including" various components or
steps, the compositions and methods can also "consist essentially
of" or "consist of" the various components and steps. All numbers
and ranges disclosed above may vary by some amount. Whenever a
numerical range with a lower limit and an upper limit is disclosed,
any number and any included range falling within the range is
specifically disclosed. In particular, every range of values (of
the form, "from about a to about b," or, equivalently, "from
approximately a to b," or, equivalently, "from approximately a-b")
disclosed herein is to be understood to set forth every number and
range encompassed within the broader range of values. Also, the
terms in the claims have their plain, ordinary meaning unless
otherwise explicitly and clearly defined by the patentee. Moreover,
the indefinite articles "a" or "an," as used in the claims, are
defined herein to mean one or more than one of the element that it
introduces. If there is any conflict in the usages of a word or
term in this specification and one or more patent or other
documents that may be incorporated herein by reference, the
definitions that are consistent with this specification should be
adopted.
* * * * *